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Biomedical subjects

L E Williams

Publications and source records attributed to L E Williams.

At least 127 records · Page 7Linked to original sources
PubMed1980

Carbon exchange rates of shoots required to utilize available acetylene reduction capacity in soybean and alfalfa root nodules.

The CO(2)-exchange rate required to make full use of available N(2)-fixation capacity, measured as acetylene reduction, was determined in soybean and alfalfa. Carbohydrates of root systems were depleted during a 40-hour dark treatment; then plants were exposed to a 24-hour light period during which different CO(2)-exchange rates were maintained with various CO(2) concentrations. In three- and four-week-old soybeans and four-week-old alfalfa plants, acetylene-reduction capacity was used fully with CO(2)-exchange rates as low as 10 milligrams CO(2) per plant per hour. In six-week-old alfalfa plants, however, acetylene reduction rates increased linearly, and apparent N(2)-fixation capacity was not used fully when CO(2)-exchange rates were higher than 40 milligrams CO(2) per plant per hour. Under the conditions established, the energy cost of N(2) fixation, measured as Delta(respiration of roots + nodules)/Deltaacetylene reduction over dark-treatment values, was 0.453 milligrams CO(2) per micromole C(2)H(4) for all rates of acetylene reduction and for both ages of soybean and alfalfa plants. Thus, root-plus-nodule respiration was not promoted by higher rates of apparent photosynthesis after C(2)H(2)-reduction capacity became saturated, and all available capacity for apparent N(2) fixation had the same energy requirement.

Journal Article↗
PubMed1980

Effect of irradiance on development of apparent nitrogen fixation and photosynthesis in soybean.

Soybeans grown with 2 millimolar NO(3) (-), which optimized apparent N(2) fixation by Rhizobium symbionts, showed significantly different rates of apparent photosynthesis and C(2)H(2) reduction during seedling development at two irradiances. Those physiological processes were lower for several weeks in plants grown at 1,500 microeinsteins per meter(2) per second than in those exposed to 700 microeinsteins per meter(2) per second. The irradiance-induced retardation was evident in short-term rates of apparent photosynthesis and N(2) fixation, as well as in measures of dry matter and total N accumulation. In spite of their previously inhibited development, plants grown at 1,500 microeinsteins per meter(2) per second were indistinguishable by day 28 from those exposed to 700 microeinsteins per meter(2) per second in terms of whole-shoot CO(2)-exchange rate; by day 35 they were identical in terms of whole-plant C(2)H(2)-reduction rate. On day 38 there was no significant difference in dry weight or N content between treatments. Shifting plants between irradiance treatments on day 21 showed that the higher irradiance also had a short-term inhibitory effect on C(2)H(2) reduction. The fact that 16 millimolar NO(3) (-) prevented the continuous exposure to 1,500 microeinsteins per meter(2) per second from inhibiting apparent photosynthesis suggested that seedlings grown on 2 millimolar NO(3) (-) with Rhizobium were N-limited. Although rates of apparent photosynthesis were similar by day 28, the additional week required to produce equal rates of apparent N(2) fixation between irradiance treatments showed that physiological adaptations of shoots, as well as photosynthesis per se, can affect root nodule activity.

Journal Article↗
PubMed1980

Effects of blood-induced infections of Plasmodium hermani on domestic and wild turkey poults.

Experimental blood-induced infections of Plasmodium hermani were studied in young domestic and laboratory-reared wild turkey poults. Anemia, splenomegaly and decreased growth rates were observed, but no mortality due to the malarial infections occurred. It is suggested that malaria, acting in concert with other factors, may contribute to mortality of wild turkey poults in Florida during the first 3 to 4 weeks after hatching.

Animals↗
PubMed1980

A study of the myocardial depressant factor and its relative influence in drug/alcohol mortality.

A shock factor, a low molecular weight peptide, has been isolated from postmortem blood. High levels of this peptide, which depresses the myocardium, were seen in cases where drug overdose or alcoholism, or both, were the cause of death. An elevated myocardial depressant factor (MDF) level also demonstrated in a fire victim and a patient in cardiogenic shock. The peptide analysis was accomplished by using an isolated cat papillary muscle followed by paper chromatographic confirmation. Postmortem electrolytes, alcohol, and various toxic agents were eliminated as causes of myocardial depression in the isolated cat papillary muscle assay. The presence of elevated MDF levels may be significant in the overall death process.

Accidents↗
PubMed1977

Effect of different killing techniques on early labeled photosynthetic products in c(4) plants.

The choice of leaf-killing technique was found to affect significantly the distribution of label among early labeled photosynthetic products in two C(4) plants, Portulaca oleracea and Zea mays. The major effect of these procedures was on the amount of amino acids present, particularly alanine, and the ratio of malate to aspartate. Killing Portulaca leaves in alcohol generally results in more alanine and the predominance of malate over aspartate. When the leaves are killed by immediate freezing, however, aspartate contained more radioactivity than malate, and alanine was present in much reduced amounts. The various methods also differ in the relative amounts of C(3) cycle compounds and other, secondary intermediates which were obtained.

Journal Article↗
PubMed1976

The colposuspension operation for urinary incontinence.

Forty-two patients with urinary incontinence and related symptoms were treated by colposuspension. Two patients were lost to follow-up and the results of surgery in the remaining 40 patients are presented and discussed. The place of vaginal surgery in women with urinary symptoms is also discussed.

Adult↗
PubMed1975

Detection of canine kidney allograft rejection with 51Cr-labeled lymphocytes.

Mongrel dogs received transplanted kidneys following total nephrectomy. The whole blood was centrifuged to separate out the lymphocytic fraction, which was tagged with 51Cr. Renal accumulation of 51Cr was followed using imaging detectors. All allograft rejections were accompanied by a simultaneous rise in the count rate. Labeled lymphocytes can be used to detect canine renal rejection, and the authors feel that this technique can be applied to man.

Animals↗